Write instructions for a Custom GPT, Claude Project or Gem

Help me set up a reusable assistant in {{platform}} for a task I do often. I need the instructions to paste in and a list of the files to attach, with a clear reason for what goes where.

The task: {{task}}
Who will use the assistant: {{users}}
What people will paste or type in each time: {{inputs}}
Rules it must follow and things it must never do: {{rules}}
Files I could attach (style guides, templates, policies, past examples): {{available_files}}

An example of a really good result for this task:
"""
{{good_example}}
"""

How to divide the work:
- Instructions hold what applies to every conversation: the role, who the users are, the steps to follow, the output format, the rules, and what to do when information is missing. Keep every essential rule here, not only in a file.
- Files hold long or changing reference material, such as policies, product facts, price lists, templates and examples. Assistants may search files for relevant passages rather than reading every word, so the instructions should name each file and say when to use it, for example "For prices, use the price list file only. If a price is not there, say so."
- Leave out anything confidential. People who use a shared assistant can often get it to reveal its instructions and file contents.

Produce:
1. A name and a one-line description for the assistant.
2. The instructions, ready to paste, in plain sections: Role, What users bring, Steps, Output format, Rules, When information is missing. Aim for 300 to 800 words; shorter is better as long as nothing essential is lost. They should be clear enough that a colleague reading them could predict what the assistant will do.
3. Files to attach: a table with the columns File, What it contains, Why it is a file and not an instruction, and How to prepare it, for example removing personal data or keeping only the current version.
4. Settings: if {{platform}} lets me switch tools such as web search or file creation on or off, which ones this assistant needs and why.
5. Four example first messages a user might send.
6. Five test requests, each with what a correct response does, including one with missing information and one that asks the assistant to break a rule.

Use only the facts I gave, and mark anything you had to assume with "[assumed: ...]". If the task is too vague to write the steps, ask me up to three questions before drafting.